Aortic filter catheter

ABSTRACT

A aortic filter catheter is used to capture potential emboli within the aorta during heart surgery and cardiopulmonary bypass. An expandable embolic filter assembly having fine filter mesh for capturing macroemboli and microemboli is mounted on a catheter shaft having a perfusion lumen with perfusion ports located upstream of the filter. The embolic filter assembly can be actively or passively deployed within the ascending aortic. The embolic filter assembly includes an aortic occlusion device, which may be a toroidal balloon, an expandable balloon or a selectively deployable external catheter flow control valve. The combined device allows percutaneous transluminal administration of cardiopulmonary bypass and cardioplegic arrest with protection from undesirable embolic events.

CROSS REFERENCE TO OTHER APPLICATIONS

[0001] This application is a divisional of U.S. patent application Ser.No. 09/158,405, filed Sep. 22, 1998, now U.S. Pat. No. 6,361,545, whichclaims the benefit of U.S. Provisional Application, serial No.60/060,117, filed Sep. 26, 1997, which are hereby incorporated byreference in their entirety.

FIELD OF THE INVENTION

[0002] The present invention relates generally to a catheter or cannulafor infusion of oxygenated blood or other fluids into a patient forcardiopulmonary support and cerebral protection. More particularly, itrelates to an arterial perfusion catheter with a deployable embolicfilter for protecting a patient from adverse effects due to emboli thatare dislodged during cardiopulmonary bypass.

BACKGROUND OF THE INVENTION

[0003] Over the past decades tremendous advances have been made in thearea of heart surgery, including such life saving surgical procedures ascoronary artery bypass grafting (CABG) and cardiac valve repair orreplacement surgery. Cardiopulmonary bypass (CPB) is an importantenabling technology that has helped to make these advances possible.Recently, however, there has been a growing awareness within the medicalcommunity and among the patient population of the potential sequelae oradverse affects of heart surgery and of cardiopulmonary bypass. Chiefamong these concerns is the potential for stroke or neurologic deficitassociated with heart surgery and with cardiopulmonary bypass. One ofthe likely causes of stroke and of neurologic deficit is the release ofemboli into the blood stream during heart surgery. Potential embolicmaterials include atherosclerotic plaques or calcific plaques fromwithin the ascending aorta or cardiac valves and thrombus or clots fromwithin the chambers of the heart. These potential emboli may bedislodged during surgical manipulation of the heart and the ascendingaorta or due to high velocity jetting (sometimes called the“sandblasting effect”) from the aortic perfusion cannula. Air thatenters the heart chambers or the blood stream during surgery throughopen incisions or through the aortic perfusion cannula is another sourceof potential emboli. Emboli that lodge in the brain may cause a strokeor other neurologic deficit. Clinical studies have shown a correlationbetween the number and size of emboli passing through the carotidarteries and the frequency and severity of neurologic damage. At leastone study has found that frank strokes seem to be associated withmacroemboli larger than approximately 100 micrometers in size, whereasmore subtle neurologic deficits seem to be associated with multiplemicroemboli smaller than approximately 100 micrometers in size. In orderto improve the outcome of cardiac surgery and to avoid adverseneurological effects it would be very beneficial to eliminate or reducethe potential of such cerebral embolic events.

[0004] Several medical journal articles have been published relating tocerebral embolization and adverse cerebral outcomes associated withcardiac surgery, e.g.: Determination or Size of Aortic Emboli andEmbolic Load During Coronary Artery Bypass Grafting; Barbut et al.; AnnThorac Surg 1997;63; 1262-7; Aortic Atheromatosis and Risks of CerebralEmbolization; Barbut et al.; J Card & Vasc Anesth, Vol 10, No 1, 1996:pp 24; Aortic Atheroma is Related to Outcome but not Numbers of EmboliDuring Coronary Bypass; Barbut et al.; Ann Thorac Surg 1997;64;454-9;Adverse Cerebral Outcomes After Coronary Artery Bypass Surgery; Roach etal.; New England J of Med, Vol 335, No 25, 1996: pp 1857-1863; Signs ofBrain Cell Injury During Open Heart Operations: Past and Present; Aberg;Ann Thorac Surg 1995;59; 1312-5; The Role of CPB Management inNeurobehavioral Outcomes After Cardiac Surgery; Murkin; Ann Thorac Surg1995;59;1308-11; Risk Factors for Cerebral Injury and Cardiac Surgery;Mills; Ann Thorac Surg 1995;59;1296-9; Brain Microemboli Associated withCardiopulmonary Bypass: A Histologic and Magnetic Resonance ImagingStudy; Moody et al.; Ann Thorac Surg 1995;59;1304-7; CNS DysfunctionAfter Cardiac Surgery: Defining the Problem; Murkin; Ann Thorac Surg1995;59; 1287+Statement of Consensus on Assessment of NeurobehavioralOutcomes After Cardiac Surgery; Murkin et al.; Ann Thorac Surg1995;59;1289-95; Heart-Brain Interactions: Neurocardiology Comes of Age;Sherman et al.; Mayo Clin Proc 62:1158-1160, 1987; Cerebral HemodynamicsAfter Low-Flow Versus No-Flow Procedures; van der Linden; Ann ThoracSurg 1995;59;1321-5; Predictors of Cognitive Decline After CardiacOperation; Newman et al.; Ann Thorac Surg 1995;59;1326-30;Cardiopulmonary Bypass: Perioperative Cerebral Blood Flow andPostoperative Cognitive Deficit; Venn et al.; Ann Thorac Surg 1995;59;1331-5; Long-Term Neurologic Outcome After Cardiac Operation; Sotaniemi;Ann Thorac Surg 1995;59;1336-9; and Macroemboli and Microemboli DuringCardiopulmonary Bypass; Blauth; Ann Thorac Surg 1995;59;1300-3.

[0005] The patent literature includes several references relating tovascular filter devices for reducing or eliminating the potential ofembolization. These and all other patents and patent applicationsreferred to herein are hereby incorporated herein by reference in theirentirety.

[0006] The following U.S. patents relate to vena cava filters: U.S. Pat.Nos. 5,549,626, 5,415,630, 5,152,777, 5,375,612, 4,793,348, 4,817,600,4,969,891, 5,059,205, 5,324,304, 5,108,418, 4,494,531. Vena cava filtersare devices that are implanted into a patient's inferior vena cava forcapturing thromboemboli and preventing them from entering the rightheart and migrating into the pulmonary arteries. These are generallydesigned for permanent implantation and are only intended to capturerelatively large thrombi, typically those over a centimeter in diameter,that could cause a major pulmonary embolism. As such, these areunsuitable for temporary deployment within a patient's aorta or forcapturing macroemboli or microemboli associated with adverseneurological outcomes. Vena cava filters are also not adapted forsimultaneously providing arterial blood perfusion in connection withcardiopulmonary bypass.

[0007] The following U.S. patents relate to vascular filter devices:U.S. Pat. Nos. 5,496,277, 5,108,419, 4,723,549, 3,996,938. These filterdevices are not of a size suitable for deployment within a patient'saorta, nor would they provide sufficient filter surface area to allowaortic blood flow at normal physiologic flow rates without anunacceptably high pressure drop across the filter. Furthermore, thesefilter devices are not adapted for simultaneously providing arterialblood perfusion in connection with cardiopulmonary bypass devices.

[0008] The following U.S. patents relate to aortic filters or aorticfilters associated with atherectomy devices: U.S. Pat. Nos. 5,662,671,5,769,816. The following international patent applications relate toaortic filters or aortic filters associated with atherectomy devices: WO97/17100, WO 97/42879, WO 98/02084. The following international patentapplication relates to a carotid artery filter: WO 98/24377. This familyof U.S. and international patents includes considerable discussion onthe mathematical relationship between blood flow rate, pressure drop,filter pore size and filter area and concludes that, for use in theaorta, it is desirable for the filter mesh to have a surface area of3-10 in², more preferably 4-9 in², 5-8 in² or 6-8 in², and mostpreferably 7-8 in². While these patents state that this characteristicis desirable, none of the filter structures disclosed in the drawingsand description of these patents appears capable of providing a filtersurface area within these stated ranges when deployed within anaverage-sized human aorta. Accordingly, it would be desirable to providea filter structure or other means that solves this technical problem byincreasing the effective surface area of the filter mesh to allow bloodflow at normal physiologic flow rates without an unacceptably highpressure drop.

SUMMARY OF THE INVENTION

[0009] In keeping with the foregoing discussion, the present inventiontakes the form of a perfusion filter catheter or cannula having anembolic filter assembly mounted on an elongated tubular catheter shaft.The elongated tubular catheter shaft is adapted for introduction into apatient's ascending aorta either by a peripheral arterial approach or bya direct aortic puncture. A fine filter mesh for capturing macroemboliand/or microemboli is mounted on the embolic filter assembly. Theembolic filter assembly has an undeployed state in which the filter iscompressed or wrapped tightly around the catheter shaft and a deployedstate in which the embolic filter assembly expands to the size of theaortic lumen and seals against the inner wall of the aorta. The embolicfilter assembly can be passively or actively deployable. Variousmechanisms are disclosed for both passive and active deployment of theembolic filter assembly. Optionally, an outer tube may cover the embolicfilter assembly when it is in the undeployed state. Radiopaque markersand/or sonoreflective markers, may be located on the catheter and/or theembolic filter assembly. Preferably, a perfusion lumen extends throughthe elongated tubular catheter shaft to one or more perfusion portsupstream of the embolic filter assembly. Oxygenated blood is perfusedthrough the perfusion lumen and any embolic materials that might bedislodged are captured in the deployed embolic filter assembly.

[0010] In order to provide a sufficient flow rate of oxygenated bloodfor support of all critical organ systems through the filter withoutexcessive pressure drop, it is preferred that the surface area of thefilter mesh be greater than twice the cross-sectional area of the aorticlumen, more preferably three, four, five or six times greater thanluminal cross section of the aorta. Preferably, the embolic filterassembly is also configured to hold at least a majority of the filtermesh away from the aortic wall when deployed to maximize the effectivefilter surface area. Several possible configurations are described forthe embolic filter assembly that meet these parameters. The embolicfilter assembly configurations described include an elongated cone, afrustum of a cone, a trumpet-shape, a modified trumpet-shape, andhelically, circumferentially and longitudinally convoluted shapes.Further configurations are described having standoff members forcentering the embolic filter assembly within the aorta and for holdingat least a majority of the filter mesh away from the aortic walls whendeployed.

[0011] Embodiments are also described that combine the perfusion filtercatheter with an aortic occlusion device, which may be a toroidalballoon, an expandable balloon or a selectively deployable externalcatheter flow control valve. The combined device allows percutaneoustransluminal administration of cardiopulmonary bypass and cardioplegicarrest with protection from undesirable embolic events. An embodiment ofthe perfusion filter catheter is described having an aortictransillumination system for locating and monitoring the position andthe deployment state of the catheter and the embolic filter assemblywithout fluoroscopy.

[0012] In use, the perfusion filter catheter is introduced into thepatient's aorta with the embolic filter assembly in a collapsed stateeither by a peripheral arterial approach or by a direct aortic puncture.The embolic filter assembly is advanced across the aortic arch and intothe ascending aorta. When the embolic filter assembly is positioned inthe ascending aorta between the aortic valve and the brachiocephalicartery, the embolic filter assembly is either actively or passivelydeployed. The position of the catheter and the deployment state of theembolic filter assembly may be monitored using fluoroscopy, ultrasound,transesophageal echography (TEE) or aortic transillumination. Once theembolic filter assembly is deployed, oxygenated blood may be infusedinto the aorta through the perfusion lumen. Any potential emboli arecaptured by the embolic filter assembly and prevented from entering theneurovasculature or other branches downstream. After use, the embolicfilter assembly is returned to the collapsed position and the catheteris withdrawn from the patient.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIGS. 1-3 show a perfusion filter catheter configured forretrograde deployment via a peripheral arterial access point.

[0014]FIG. 1 is a cutaway perspective view of the perfusion filtercatheter deployed within the aorta via femoral artery access.

[0015]FIG. 2 shows the distal end of the catheter with the embolicfilter assembly in a deployed state.

[0016]FIG. 3 shows the distal end of the catheter with the embolicfilter assembly in a collapsed state for insertion or withdrawal of thedevice from the patient.

[0017] FIGS. 4-6 show a method of passively deploying an embolic filterassembly on a perfusion filter catheter.

[0018]FIGS. 7, 7A, 8 and 8A show a flow-assisted method of passivelydeploying an embolic filter assembly on a perfusion filter catheter.

[0019] FIGS. 9-11 show a method of passively deploying a self-expandingand self-supporting embolic filter assembly on a perfusion filtercatheter.

[0020] FIGS. 12-14 show a method of actively deploying an embolic filterassembly with a collapsible outer hoop and a plurality of actuationwires.

[0021] FIGS. 15-17 show a method of actively deploying an embolic filterassembly with an inflatable filter support structure.

[0022] FIGS. 18-20 show a method of actively deploying a spiral flutedembolic filter assembly by twisting or furling the embolic filterassembly around an inner catheter shaft.

[0023] FIGS. 21-23 show a method of actively deploying acircumferentially pleated embolic filter assembly on a perfusion filtercatheter.

[0024]FIG. 24 shows a perfusion filter catheter adapted for retrogradedeployment via subclavian artery access.

[0025] FIGS. 25-27 show a perfusion filter catheter adapted forantegrade deployment via direct aortic puncture.

[0026]FIGS. 28 and 29 show a perfusion filter catheter having an embolicfilter assembly with a graded porosity filter screen.

[0027]FIGS. 30 and 30A show a perfusion filter catheter having alongitudinally fluted embolic filter assembly.

[0028]FIGS. 31 and 31A show a perfusion filter catheter having alongitudinally ribbed embolic filter assembly.

[0029]FIG. 32 shows a perfusion filter catheter having an embolic filterassembly that is surrounded by a cage of longitudinally orientedstandoff members.

[0030]FIG. 33 shows a perfusion filter catheter having an embolic filterassembly that is surrounded by a cage of coiled wire standoff members.

[0031]FIG. 34 shows a perfusion filter catheter having an embolic filterassembly that is surrounded by a cage of coarse netting.

[0032]FIG. 35 shows a cutaway view of a perfusion filter catheter havingan embolic filter assembly that is surrounded by a fender made from aporous foam or a fibrous network.

[0033]FIGS. 36 and 37 show an alternate embodiment of a perfusion filtercatheter with a passively deployed embolic filter assembly.

[0034] FIGS. 38-41 show an alternate embodiment of a perfusion filtercatheter with an actively deployed embolic filter assembly having afilter support structure with a preshaped, superelastic actuation wire.

[0035]FIGS. 42 and 43 show another alternate embodiment of a perfusionfilter catheter with an actively deployed embolic filter assembly havinga filter support structure with a preshaped, superelastic wire pursestring loop.

[0036]FIGS. 44 and 45 show another alternate embodiment of a perfusionfilter catheter with an actively deployed inflatable embolic filterassembly.

[0037] FIGS. 46-50 show the operation of an embodiment of a perfusionfilter catheter that combines an embolic filter assembly with a toroidalballoon aortic occlusion device.

[0038]FIG. 51 shows an embodiment of a perfusion filter catheter thatcombines an embolic filter assembly with an inflatable balloon aorticocclusion device.

[0039]FIG. 52 shows an embodiment of a perfusion filter catheter thatcombines an embolic filter assembly with a selectively deployableexternal catheter flow control valve.

[0040]FIG. 53 shows an embodiment of a perfusion filter catheter with anembolic filter assembly having areas of different filter porosity.

[0041]FIG. 54 shows an embodiment of a perfusion filter catheter with afiberoptic system for aortic transillumination.

DETAILED DESCRIPTION OF THE INVENTION

[0042] FIGS. 1-3 show a perfusion filter catheter 100 according to thepresent invention configured for retrograde deployment via a peripheralarterial access point. FIG. 1 is a cutaway perspective view of theperfusion filter catheter 100 deployed within the aorta of a patient viafemoral artery access. FIG. 2 shows the distal end of the catheter 100with the embolic filter assembly 102 in a deployed state. FIG. 3 showsthe distal end of the catheter with the embolic filter assembly 102′ ina collapsed state for insertion or withdrawal of the device from thepatient.

[0043] Referring now to FIG. 1, the perfusion filter catheter 100includes an elongated tubular catheter shaft 104 with a proximal end 108and distal end 110. The catheter shaft 104 is preferably extruded of aflexible thermoplastic material or a thermoplastic elastomer. Suitablematerials for the catheter shaft 104 include, but are not limited to,polyvinylchloride, polyurethane, polyethylene, polypropylene, polyamides(nylons), and alloys or copolymers thereof, as well as braided, coiledor counterwound wire or filament reinforced composites. The tubularcatheter shaft 104 may have a single lumen or multilumen construction.In the exemplary embodiment shown, the catheter 100 has a singleperfusion lumen 106 extending from the proximal end 108 to the distalend 110 of the catheter shaft 104. The perfusion lumen 106 is open atthe distal end 110 of the catheter shaft 104. The distal end 110 of thecatheter shaft 104 may have a simple beveled or rounded distal edge, asshown, or it may include additional side ports or a flow diffuser toreduce jetting when oxygenated blood is infused through the perfusionlumen 106. The proximal end 108 of the elongated tubular catheter shaft104 is adapted for connecting the perfusion lumen 106 to acardiopulmonary bypass pump or other source of oxygenated blood usingstandard barb connectors or other connectors, such as a standard luerfitting (not shown). Preferably, the catheter shaft 104 is made withthin walled construction to maximize the internal diameter and thereforethe flow rate of the perfusion lumen 106 for a given outside diameterand length of the catheter shaft 104. Thin walled construction alsoallows the outside diameter of the catheter shaft 104 to be minimized inorder to reduce the invasiveness of the procedure and to reduce traumaat the insertion site. The perfusion lumen 106 should be configured toallow sufficient blood flow to preserve organ function without hemolysisor other damage to the blood. For standard cardiopulmonary supporttechniques, a catheter shaft 104 of 18-24 French size (6-8 mm outsidediameter) is sufficient to deliver the requisite 3-4 liters ofoxygenated blood to preserve organ function. For low flowcardiopulmonary support techniques, such as described in commonly owned,copending patent application Ser. No. 60/084,835, filed May 8, 1998which is hereby incorporated by reference, the size of the cathetershaft 104 can be reduced to 9-18 French size (3-6 mm outside diameter)for delivering 0.5-3 liters of oxygenated blood to preserve organfunction. The catheter shaft 104 should have a length sufficient toreach from the arterial access point where it is inserted to theascending aorta of the patient. For femoral artery deployment, thecatheter shaft 104 preferably has a length from approximately 80-120 cm.

[0044] A deployable embolic filter assembly 102 is located just proximalto the distal end 110 of the catheter shaft 104. The embolic filterassembly 102 includes a filter screen 112 made of a fine mesh material.In this exemplary embodiment and each of the other embodiments describedbelow, the fine mesh material of the filter screen 112 may be a woven orknitted fabric, such as Dacron polyester or nylon mesh, or other textilefabrics, or it may be a nonwoven fabric, such as a spun bondedpolyolefin or expanded polytetrafluoroethylene or other nonwovenmaterials. The fine mesh material of the filter screen 112 may be woven,knitted or otherwise formed from monofilament or multifilament fibers.The fine mesh material of the filter screen 112 may also be a fine wiremesh or a combination of wire and textile fibers. Alternatively, thefine mesh material of the filter screen 112 may be an open cell foammaterial. The fine mesh material of the filter screen 112 must benontoxic and hemocompatible, that is, non-thrombogenic andnon-hemolytic. Preferably, the fine mesh material of the filter screen112 has a high percentage of open space, with a uniform pore size. Thepore size of the filter screen 112 can be chosen to capture macroembolionly or to capture macroemboli and microemboli. In most cases the poresize of the filter screen 112 will preferably be in the range of 1-200micrometers. For capturing macroemboli only, the pore size of the filterscreen 112 will preferably be in the range of 50-200 micrometers, morepreferably in the range of 80-100 micrometers. For capturing macroemboliand microemboli, the pore size of the filter screen 112 will preferablybe in the range of 1-100 micrometers, more preferably in the range of5-20 micrometers. In other applications, such as for treatingthromboembolic disease, a larger pore size, e.g. up to 1000 micrometers(1 mm) or larger, would also be useful. In some embodiments, acombination of filter materials having different pore sizes may be used.

[0045] Alternatively or additionally the material of the filter screenin each embodiment of the filter catheter may be made of or coated withan adherent material or substance to capture or hold embolic debriswhich comes into contact with the filter screen within the embolicfilter assembly. Suitable adherent materials include, but are notlimited to, known biocompatible adhesives and bioadhesive materials orsubstances, which are hemocompatible and non-thrombogenic. Suchmaterials are known to those having ordinary skill in the art and aredescribed in, among other references, U.S. Pat. Nos. 4,768,523,5,055,046, 5,066,709, 5,197,973, 5,225,196, 5,374,431, 5,578,310,5,645,062, 5,648,167, 5,651,982, and 5,665,477. In one particularlypreferred embodiment, only the upstream side of the elements of thefilter screen are coated with the adherent material to positivelycapture the embolic debris which comes in contact with the upstream sideof the filter screen after entering the filter assembly. Other bioactivesubstances, for example, heparin or thrombolytic agents, may beimpregnated into or coated on the surface of the filter screen materialor incorporated into an adhesive coating.

[0046] The embolic filter assembly 102 is movable between a collapsedstate, as shown in FIG. 3, and an expanded or deployed state, as shownin FIGS. 1 and 2. The filter screen 112 may be attached directly to thecatheter shaft 104 and it may constitute the entire embolic filterassembly 102, particularly if the filter screen 112 is made of aresilient or semirigid fabric that has enough body to be self-supportingin the deployed state. Generally, however, the embolic filter assembly102 will also include a filter support structure 114, particularly if ahighly flexible or flaccid material is used for the filter screen 112.The filter support structure 114 attaches and supports the filter screen112 on the catheter shaft 104. In the illustrative embodiment of FIGS.1-3, the filter support structure 114 is constructed with an outer hoop116 and a plurality of struts 118 which extend approximately radiallyfrom a ring-shaped hub 126 that is mounted on the catheter shaft 104. Inthis case four struts 118 are shown, however, two, three or more struts118 may be used. The open distal end 122 of the filter screen 112 isattached to the outer hoop 116 and the proximal end 120 of the filterscreen 112 is sealingly attached to the catheter shaft 104. When theembolic filter assembly 102 is deployed, the outer hoop 116 of thefilter support structure 114 holds the open distal end 122 of the filterscreen 112 against the inner wall of the aorta, as shown in FIG. 1. Toaccommodate most normal adult aortas, the outer hoop 116 of the filtersupport structure 114 and the distal end 122 of the filter screen 112have a diameter of approximately 2.5 to 4 cm, plus or minus 0.5 cm.Larger and smaller diameter filter support structures 114 may be made toaccommodate patients with distended or Marfan syndrome aortas or forpediatric patients.

[0047] The embolic filter assembly 102 may be deployed by a passivemeans or by an active means. Passive means for deploying the embolicfilter assembly 102 could include using the elastic memory of the filterscreen 112 and/or the filter support structure 114 to deploy the embolicfilter assembly 102, and/or using pressure from the blood flow in theaorta to deploy the embolic filter assembly 102. By contrast, activemeans for deploying the embolic filter assembly 102 could include one ormore actuation members within the catheter shaft 104 for mechanicallyactuating the filter support structure 114 to deploy the embolic filterassembly 102 from the proximal end 108 of the catheter 100. Shape memorymaterials may also be used as actuation members for deploying theembolic filter assembly 102. Alternatively, active means for deployingthe embolic filter assembly 102 could include one or more lumens withinthe catheter shaft 104 for hydraulically actuating the filter supportstructure 114 to deploy the embolic filter assembly 102. Passive meansmay be used to augment the action of the active deployment means. Asshown in FIG. 3, an outer tube 124 may be provided to cover the embolicfilter assembly 102 when it is in the collapsed state in order to createa smooth outer surface for insertion and withdrawal of the catheter 100and to prevent premature deployment of the embolic filter assembly 102,particularly if passive deployment means are used.

[0048] The perfusion filter catheter 100 is prepared for use by foldingor compressing the embolic filter assembly 102 into a collapsed statewithin the outer tube 124, as shown in FIG. 3. The distal end 110 of thecatheter 100 is inserted into the aorta in a retrograde fashion.Preferably, this is done through a peripheral arterial access, such asthe femoral artery or subclavian artery, using the Seldinger techniqueor an arterial cutdown. Alternatively, the catheter 100 may beintroduced directly through an incision into the descending aorta afterthe aorta has been surgically exposed. The embolic filter assembly 102is advanced up the descending aorta and across the aortic arch while inthe collapsed state. The position of the catheter 100 may be monitoredusing fluoroscopy or ultrasound, such as transesophageal echography(TEE). Appropriate markers, which may include radiopaque markers and/orsonoreflective markers, may be located on the distal end 110 of thecatheter 100 and/or the embolic filter assembly 102 to enhance imagingand to show the position of the catheter 100 and the deployment state ofthe embolic filter assembly 102. When the distal end 110 of the catheter100 is positioned in the ascending aorta between the aortic valve andthe brachiocephalic artery, the outer tube 124 is withdrawn and theembolic filter assembly 102 is deployed, as shown in FIG. 3. Optionally,a distal portion of the catheter shaft 104 may be precurved to match thecurvature of the aortic arch to aid in placement and stabilization ofthe catheter 100 and the embolic filter assembly 102 within the aorta.Once the embolic filter assembly 102 is deployed, oxygenated blood maybe infused through the perfusion lumen 106 to augment cardiac output ofthe beating heart or to establish cardiopulmonary bypass so that theheart can be arrested. Any potential emboli are captured by the filterscreen 112 and prevented from entering the neurovasculature or otherbranches downstream. After use, the embolic filter assembly 102 isreturned to the collapsed position and the catheter 100 is withdrawnfrom the patient.

[0049] Preferably, the embolic filter assembly 102 is configured sothat, when it is in the deployed state, at least a majority of thefilter screen 112 is held away from the aortic walls so that flowthrough the pores of the filter screen 112 is not occluded by contactwith the aortic wall. In addition, this also assures that blood flowinto the side branches of the aorta will not be obstructed by the filterscreen 112. In this way, each side branch of the aorta will receive thebenefit of flow through the full surface area of the filter screen 112so that blood flow is not restricted by the area of the ostium of eachside branch. In the illustrative embodiment of FIGS. 1-3, the filterscreen 112 has a roughly conical shape with an open distal end 122. Theconical shape holds the fine mesh material of the filter screen 112 awayfrom the aortic walls and away from the ostia of the side branches sothat blood can flow freely through the pores of the filter screen 112.

[0050] Deployment of the embolic filter assembly 102 can be accomplishedpassively or actively. FIGS. 4-11 show various methods of passivelydeploying the embolic filter assembly 102 and FIGS. 12-23 show variousmethods of actively deploying the embolic filter assembly 102. FIGS. 4-6show one method of passively deploying the embolic filter assembly 102.In this exemplary embodiment, the outer hoop 116 and the struts 118 ofthe filter support structure 114 are made of an elastic or superelasticmetal or polymer, for example a superelastic nickel/titanium alloy,which is easily deformed into the collapsed state and which expandspassively from the collapsed state to the deployed state. To place theembolic filter assembly 102 in the collapsed position shown in FIG. 4,the struts 118 are folded back in the proximal direction and the outerhoop 116 is folded against the catheter shaft 104 along with thematerial of the filter screen 112. The outer tube 124 is placed over thefolded embolic filter assembly 102 to hold it in the collapsed position.Once the perfusion filter catheter 100 is in position within thepatient's aorta, the outer tube 124 is pulled back, as shown in FIG. 5,to release the folded embolic filter assembly 102. The outer hoop 116and struts 118 expand the filter screen 112 to its deployed position,shown in FIG. 6, and hold the open distal end 122 of the filter screen112 against the inner wall of the aorta, as shown in FIG. 1. After use,the embolic filter assembly 102 is returned to the collapsed position byadvancing the outer tube 124 distally over the filter screen 112 and thefilter support structure 114, then the catheter 100 is withdrawn fromthe patient.

[0051]FIGS. 7, 7A, 8 and 8A show another method of passively deployingan embolic filter assembly 132 on a perfusion filter catheter 130. Inthis embodiment, the filter support structure includes a plurality ofstruts 136 which are hinged or flexibly attached at their inner,proximal ends to the catheter shaft 134. The struts 136 may be made ofeither a metal or a polymer. The distal end 138 of the filter screen 140is attached to the struts 136 along an outer, distal portion of thestruts 136. The proximal end 146 of the filter screen 140 is sealinglyattached to the catheter shaft 134. The portion of the filter screen 140attached to the struts 136 forms a skirt 142 along the distal edge ofthe filter assembly 132. The remaining portion of the filter screen 140forms a filter pocket 144 along the proximal end of the filter assembly132. The skirt 142 and the filter pocket 144 may be made of the samefilter material or they may be made of different filter materials havingdifferent porosities. The skirt 142 of the filter screen 140 may even bemade of a nonporous material.

[0052] The embolic filter assembly 132 is folded into the collapsedposition shown in FIG. 7 by folding the struts 136 in the distaldirection so they lie against the catheter shaft 134. FIG. 7A is acutaway view of the catheter 130 with the embolic filter assembly 132 inthe collapsed position. The material of the filter screen 140 is foldedaround or in between the struts 136. The outer tube 148 is placed overthe folded embolic filter assembly 132 to hold it in the collapsedposition. Once the perfusion filter catheter 130 is in position withinthe patient's aorta, the outer tube 148 is pulled back, as shown in FIG.8, to release the folded embolic filter assembly 132. Blood flow withinthe aorta catches the skirt 142 of the filter screen 140 and forces theembolic filter assembly 132 to open into the deployed position shown inFIG. 8. FIG. 8A is a cutaway view of the catheter 130 with the embolicfilter assembly 132 in the deployed position. Optionally, the struts 136may be resiliently biased toward the deployed position to assist inpassive deployment of the embolic filter assembly 132. As the embolicfilter assembly 132 is passively opened by the blood flow, the skirt 142of the filter screen 140 naturally and atraumatically seals against theaortic wall. The passive deployment of the skirt 142 also naturallycompensates for patient-to-patient variations in aortic luminaldiameter. The filter pocket 144 of the embolic filter assembly 132 isheld away from the aortic walls and away from the ostia of the sidebranches so that blood can flow freely through the pores of the filterscreen 140.

[0053] FIGS. 9-11 show another method of passively deploying an embolicfilter assembly 152 on a perfusion filter catheter 150. In thisembodiment, the filter screen 154 is self-expanding and self-supporting,so no separate filter support structure is needed. Preferably, theembolic filter assembly 152 includes resilient wires or filaments 156that are interwoven with the fibers of the filter screen 154.Alternatively, the resilient wires or filaments 156 may be attached tothe interior or exterior surface of the filter screen 154 fabric. Theresilient wires or filaments 156 may be made of either a polymer or ametal, such as an elastic or superelastic alloy. In one preferredembodiment, the resilient wires or filaments 156, and preferably thefibers of the filter screen 154 as well, are woven at an angle to thelongitudinal axis of the embolic filter assembly 152, so that theembolic filter assembly 152 can expand and contract in diameter bychanging the angle of the wires or filaments 156. Generally, as theembolic filter assembly 152 expands in diameter, the angle between thewires or filaments 156 and the longitudinal axis of the embolic filterassembly 152 increases and the embolic filter assembly 152 may alsoforeshorten. The resilient wires or filaments 156 urge the embolicfilter assembly 152 to expand to the deployed position. The proximal end158 of the filter screen 154 is sealingly attached to the catheter shaft162.

[0054] The perfusion filter catheter 150 is shown in FIG. 9 with theembolic filter assembly 152 compressed into the collapsed position. Theembolic filter assembly 152 compresses in diameter smoothly withoutfolding as the resilient wires or filaments 156 and the fibers of thefilter screen 154 decrease their angle with respect to the longitudinalaxis of the embolic filter assembly 152. An outer tube 164 holds theembolic filter assembly 152 in the collapsed position. Once theperfusion filter catheter 150 is in position within the patient's aorta,the outer tube 164 is pulled back, which allows the embolic filterassembly 152 to expand, as shown in FIG. 10. As the embolic filterassembly 152 expands, the angle between the wires or filaments 156 andthe longitudinal axis of the embolic filter assembly 152 increases andthe embolic filter assembly 152 foreshortens slightly. FIG. 11 shows theembolic filter assembly 152 fully expanded in the deployed position. Theresilient wires or filaments 156 are preformed so that, when deployed,the filter screen 154 has a roughly conical shape with an open distalend 160. The conical shape holds the filter screen 154 away from theaortic walls and away from the ostia of the side branches so that bloodcan flow freely through the pores of the filter screen 154. The distalend 160 of the embolic filter assembly 152 seals against the aorticwall. The self-expanding aspect of the embolic filter assembly 152naturally compensates for patient-to-patient variations in aorticluminal diameter.

[0055] In alternate embodiments, the resilient wires or filaments 156may be preformed to other geometries so that the filter screen 154 ofthe embolic filter assembly 152 assumes a different configuration whendeployed, including each of the other configurations discussed withinthis patent specification.

[0056] FIGS. 12-14 show one method of actively deploying an embolicfilter assembly 168 on a perfusion filter catheter 166. In thisexemplary embodiment, the filter support structure 170 includes acollapsible outer hoop 172 and a plurality of actuation wires 174. Thedistal end 176 of the filter screen 180 is attached to the outer hoop172 and the proximal end 182 of the filter screen 180 is sealinglyattached to the catheter shaft 184. The actuation wires 174 are slidablyreceived within actuation wire lumens 186 located in the outer wall ofthe catheter shaft 184. The actuation wires 174 exit the actuation wirelumens 186 through side ports 188 located near the distal end of thecatheter shaft 184. The actuation wires 174 and the outer hoop 172 areeach made of a resilient polymer or a metal, such as stainless steel,nickel/titanium alloy or the like.

[0057] The perfusion filter catheter 166 is shown in FIG. 12 with theembolic filter assembly 168 compressed into the collapsed position. Theactuation wires 174 are withdrawn into the actuation wire lumens 186through the side ports 188 and the outer hoop 172 is folded or collapsedagainst the catheter shaft 184. The material of the filter screen 180 isfolded or collapsed around the catheter shaft 184. An outer tube 190covers the embolic filter assembly 168 in the collapsed position tofacilitate insertion of the catheter 166. Once the perfusion filtercatheter 150 is in position within the patient's aorta, the outer tube190 is pulled back to expose the embolic filter assembly 152. Then, theactuation wires 174 are advanced distally to expand the outer hoop 172and the filter screen 180, as shown in FIG. 13. FIG. 14 shows theembolic filter assembly 168 fully expanded in the deployed position. Inthis exemplary embodiment, the filter screen 180 is configured as afrustum of a cone with an open distal end 176. The outer hoop 172 at thedistal end 176 of the filter screen 180 seals against the aortic wall.

[0058] FIGS. 15-17 show another method of actively deploying an embolicfilter assembly 202 on a perfusion filter catheter 200. In thisembodiment, the filter support structure 204 includes an outer hoop 206and a plurality of struts 208, which are all interconnected hollowtubular members. Preferably, the outer hoop 206 and the struts 208 aremade of a flexible polymeric material. The filter support structure 204is connected to an inflation lumen 210, which parallels the perfusionlumen 218 within the catheter shaft 212. At its proximal end, theinflation lumen 210 branches off from the catheter shaft 212 to a sidearm 214 with a luer fitting 216 for connecting to a syringe or otherinflation device. By way of example, this embodiment of the embolicfilter assembly 202 is shown with a trumpet-shaped filter screen 220.The filter screen 220 includes a skirt portion 222 extending distallyfrom a proximal, filter pocket 224. The skirt portion 222 is in theshape of a frustum of a cone with an open distal end, which is attachedto the outer hoop 206. The filter pocket 224 is roughly cylindrical inshape with a closed proximal end, which is sealingly attached to thecatheter shaft 212. The skirt 222 and the filter pocket 224 may be madeof the same filter material or they may be made of different filtermaterials having different porosities. The skirt 222 of the filterscreen 220 may even be made of a nonporous material.

[0059] The perfusion filter catheter 200 is shown in FIG. 17 with theembolic filter assembly 202 folded into a collapsed position. The outerhoop 206 and the struts 208 of the filter support structure 204 aredeflated and the material of the filter screen 220 is folded orcollapsed around the catheter shaft 212. An outer tube 226 covers theembolic filter assembly 202 in the collapsed position to facilitateinsertion of the catheter 200. Optionally, the outer tube 226 may have aslit or a weakened longitudinal tear line along its length to facilitateremoval of the outer tube 226 over the side arm 214 at the proximal endof the catheter 200. Once the perfusion filter catheter 200 is inposition within the patient's aorta, the outer tube 226 is pulled backto expose the embolic filter assembly 202. Then, the embolic filterassembly 202 is deployed by inflating the outer hoop 206 and the struts208 with fluid injected through the inflation lumen 210 to activelyexpand the filter support structure 204, as shown in FIG. 16. When theembolic filter assembly 202 is deployed, the outer hoop 206 of thefilter support structure 204 seals against the inner wall of the aorta,as shown in FIG. 15. Preferably, at least the outer wall of the outerhoop 206 is somewhat compliant when inflated in order to compensate forpatient-to-patient variations in aortic luminal diameter.

[0060] FIGS. 18-20 show another method of actively deploying an embolicfilter assembly 232 on a perfusion filter catheter 230. In thisembodiment, the filter support structure 234 includes an outer hoop 236and a plurality of struts 238, which are connected to an inner cathetershaft 240. The outer hoop 236 and the struts 238 may be made of aresilient polymer or metal, for example a superelastic nickel/titaniumalloy. The distal end 242 of the filter screen 244 is attached to theouter hoop 236. The proximal end 246 of the filter screen 244 issealingly attached to an outer catheter shaft 250. The inner cathetershaft 240 is slidably and rotatably received within the outer cathetershaft 250. Preferably, the filter screen 244 has one or more spiralgrooves or flutes 248 that wind helically around the filter screen 244.

[0061] The embolic filter assembly 232 is folded into the collapsedposition shown in FIG. 20 by extending and rotating the inner cathetershaft 240 in a first direction with respect to the outer catheter shaft250. This collapses the filter support structure 234 back against theinner catheter shaft 240 and furls the filter screen 244 around theinner catheter shaft 240. The spiral flutes 248 in the filter screen 244help it to collapse smoothly around the inner catheter shaft 240. Anouter tube 252 covers the embolic filter assembly 232 in the collapsedposition to facilitate insertion of the catheter 230. Once the perfusionfilter catheter 230 is in position within the patient's aorta, the outertube 252 is pulled back to expose the embolic filter assembly 232. Then,the embolic filter assembly 232 is deployed by rotating the innercatheter shaft 240 in the opposite direction with respect to the outercatheter shaft 250 and allowing it to retract slightly, as shown in FIG.19. The filter support structure 234 and the filter screen 244 willexpand within the aorta and the distal end 242 of the filter screen 244will seal against the aortic wall, as shown in FIG. 18. When it is inthe deployed position, the spiral flutes 248 of the embolic filterassembly 232 hold most of the filter screen 244 away from the aorticwalls and away from the ostia of the side branches so that blood canflow freely through the pores of the filter screen 244. After use, theembolic filter assembly 232 is returned to the collapsed position asdescribed above and the catheter 230 is withdrawn from the patient.

[0062] The coaxial arrangement of the inner catheter shaft 240 and theouter catheter shaft 250 in this embodiment of the perfusion filtercatheter 230 creates an annular space that can optionally be used as alumen 258 to aspirate potential emboli that are captured by the filterscreen 244. To facilitate this, a side arm 254 with a luer fitting and asliding hemostasis valve 256 may be added to the proximal end of theouter catheter shaft 250, as shown in FIG. 18.

[0063] FIGS. 21-23 show another method of actively deploying an embolicfilter assembly 262 on a perfusion filter catheter 260. In thisembodiment, the filter support structure 234 includes an outer hoop 266and a plurality of struts 268, which are connected to an inner cathetershaft 270. The outer hoop 266 and the struts 268 may be made of aresilient polymer or metal, for example a superelastic nickel/titaniumalloy. The distal end 272 of the filter screen 274 is attached to theouter hoop 266. The proximal end 276 of the filter screen 274 issealingly attached to an outer catheter shaft 280. The inner cathetershaft 270 is slidably received within the outer catheter shaft 280.Preferably, the filter screen 274 has a series of circumferential pleats278 that give the filter screen 274 an accordion appearance.

[0064] The embolic filter assembly 262 is folded into the collapsedposition shown in FIG. 23 by extending the inner catheter shaft 270distally with respect to the outer catheter shaft 280. This collapsesthe filter support structure 264 back against the inner catheter shaft270 and collapses the circumferential pleats 248 of the filter screen274 against the inner catheter shaft 270. An outer tube 282 covers theembolic filter assembly 262 in the collapsed position to facilitateinsertion of the catheter 260. Once the perfusion filter catheter 260 isin position within the patient's aorta, the outer tube 282 is pulledback to expose the embolic filter assembly 262. Then, the embolic filterassembly 262 is deployed by retracting the inner catheter shaft 270proximally with respect to the outer catheter shaft 280, as shown inFIG. 22. The filter support structure 264 and the filter screen 274 willexpand within the aorta and the distal end 272 of the filter screen 274will seal against the aortic wall, as shown in FIG. 21. When it is inthe deployed position, the circumferential pleats 278 of the embolicfilter assembly 262 hold the majority of the filter screen 274 away fromthe aortic walls and away from the ostia of the side branches so thatblood can flow freely through the pores of the filter screen 274. Afteruse, the embolic filter assembly 262 is returned to the collapsedposition as described above and the catheter 260 is withdrawn from thepatient.

[0065] As with the previous embodiment, the coaxial arrangement of theinner catheter shaft 270 and the outer catheter shaft 280 in thisembodiment of the perfusion filter catheter 260 creates an annular spacethat can optionally be used as a lumen 288 to aspirate potential embolithat are captured by the filter screen 274. To facilitate this, a sidearm 284 with a luer fitting and a sliding hemostasis valve 286 may beadded to the proximal end of the outer catheter shaft 280, as shown inFIG. 21.

[0066] Active deployment of the embolic filter assembly can also beaccomplished with any of the preceding embodiments by using shape memorymaterials, such as a nickel/titanium alloy, to construct the filtersupport structure and/or the actuation members. The transitiontemperature of the shape memory material should be chosen to be close tonormal body temperature so that extreme temperature variations will notbe necessary for deployment. The shape memory material of the filtersupport structure should be annealed in the deployed position to confera shape memory in this configuration. Then, the embolic filter assemblyshould be cooled below the transition temperature of the shape memorymaterial, so that the filter support structure is malleable and can beshaped into a collapsed position. Depending on the transitiontemperature, this can be done at room temperature or in iced salinesolution. If desired, an outer tube can be placed over the embolicfilter assembly to facilitate catheter insertion and to avoid prematuredeployment. Once the perfusion filter catheter is in position within thepatient's aorta, the outer tube is pulled back to expose the embolicfilter assembly and the filter support structure is heated above thetransition temperature to deploy the embolic filter assembly. Dependingon the transition temperature of the shape memory material, the filtersupport structure can be passively heated by body heat (accounting, ofcourse, for decreased body temperature during hypothermiccardiopulmonary support methods) or it can be self-heated by applying anelectrical current through the filter support structure. When heated,the filter support structure expands to its annealed configurationwithin the aorta. After use, the embolic filter assembly is returned tothe collapsed position by advancing the outer tube distally over thefilter screen and the filter support structure, then the catheter iswithdrawn from the patient.

[0067] The foregoing examples of the perfusion filter catheter of thepresent invention showed retrograde deployment of the device within theaorta via femoral artery access. Each of the described embodiments ofthe perfusion filter catheter can also be adapted for retrogradedeployment via subclavian artery access or for antegrade or retrogradedeployment via direct aortic puncture.

[0068]FIG. 24 shows a perfusion filter catheter 290 which is adapted forretrograde deployment via subclavian artery access. In this exemplaryembodiment, the perfusion filter catheter 290 is depicted with atrumpet-style, passively-deployed embolic filter assembly 292. Becauseit is intended for subclavian artery access, the perfusion filtercatheter 290 has a tubular catheter shaft 294 with a length ofapproximately 60-90 cm. Because of the shorter length, as compared tothe femoral version of the catheter, the outside diameter of thecatheter shaft 294 can be reduced to 12-18 French size (4-6 mm outsidediameter) for delivering the 3-4 liters of oxygenated blood needed topreserve organ function. The reduced diameter of the catheter shaft 294is especially advantageous for subclavian artery delivery of thecatheter 290. To further reduce the size of the catheter system forsubclavian or femoral artery delivery, the outer tube 296 may be adaptedfor use as an introducer sheath by the addition of an optionalhemostasis valve 298 at the proximal end of the outer tube 296. Thiseliminates the need for a separate introducer sheath for introducing thecatheter 290 into the circulatory system.

[0069] In use, the perfusion filter catheter 290 is introduced into thesubclavian artery with the embolic filter assembly 292 in a collapsedstate within the outer tube 296, using the Seldinger technique or anarterial cutdown. The embolic filter assembly 292 is advanced across theaortic arch while in the collapsed state. The position of the catheter292 may be monitored using fluoroscopy or ultrasound, such astransesophageal echography (TEE). Radiopaque markers and/orsonoreflective markers, may be located on the catheter 290 and/or theembolic filter assembly 292 to enhance imaging and to show the positionof the catheter 290 and the deployment state of the embolic filterassembly 292. When the distal end of the catheter 290 is positioned inthe ascending aorta between the aortic valve and the brachiocephalicartery, the outer tube 296 is withdrawn and the embolic filter assembly292 is either actively or passively deployed, as shown in FIG. 24. Oncethe embolic filter assembly 292 is deployed, oxygenated blood may beinfused into the aorta through the tubular catheter shaft 294. Anypotential emboli are captured by the embolic filter assembly 292 andprevented from entering the neurovasculature or other branchesdownstream. After use, the embolic filter assembly 292 is returned tothe collapsed position and the catheter 290 is withdrawn from thepatient.

[0070] Retrograde deployment of the perfusion filter catheter 290 viadirect aortic puncture is quite similar to introduction via subclavianartery access, except that the catheter 290 is introduced directly intothe descending aorta after it has been surgically exposed, for exampleduring open-chest or minimally invasive cardiac surgery. Because of thedirect aortic insertion, the length and the diameter of the cathetershaft 294 may be further reduced.

[0071] FIGS. 25-27 show a perfusion filter catheter 300 which is adaptedfor antegrade deployment via direct aortic puncture. In this exemplaryembodiment, the perfusion filter catheter 300 is depicted with ahybrid-style embolic filter assembly 302, which is a compromise betweenthe conical filter screen and the trumpet-style filter screen previouslydescribed. Because the catheter 300 is introduced directly into theascending aorta, the catheter shaft 304 can be reduced to a length ofapproximately 20-60 cm and an outside diameter of approximately 12-18French size (4-6 mm outside diameter) for delivering the 3-4 liters ofoxygenated blood needed to preserve organ function duringcardiopulmonary bypass. An important modification that must be made tothe catheter 300 for antegrade deployment is that the perfusion port orports 306 which connect to the perfusion lumen 308 must exit thecatheter shaft 304 proximal to the filter screen 310 so that fluid flowwill come from the upstream side of the embolic filter assembly 302. Thecatheter shaft 304 need not extend all the way to the distal end of thefilter screen 310. The filter screen 310 may be entirely supported bythe filter support structure 312, particularly if the embolic filterassembly 302 is to be passively deployed. Alternatively, a smalldiameter filter support member 314 may extend from the catheter shaft304 to the distal end of the filter screen 310. If the embolic filterassembly 302 is intended to be actively deployed, the filter supportmember 314 may be slidably and/or rotatably received within the cathetershaft 304. Either of these configurations allows the embolic filterassembly 302 to be folded or compressed to a size as small as thediameter of the catheter shaft 304 to facilitate insertion of thecatheter 300. Optionally, an outer tube 316 may be placed over thefolded embolic filter assembly 302 to hold it in the collapsed position.

[0072] In use, the ascending aorta of the patient is surgically exposed,using open-chest or minimally invasive surgical techniques. A pursestring suture 318 is placed in the ascending aorta and an aortotomyincision is made through the aortic wall. The catheter 300, with theembolic filter assembly 302 in the collapsed position within the outertube 316, is inserted through the aortotomy and advanced antegrade intothe aortic arch. When the proximal end of the embolic filter assembly302 is positioned in the ascending aorta between the aortic valve andthe brachiocephalic artery, the outer tube 316 is withdrawn and theembolic filter assembly 302 is either actively or passively deployed, asshown in FIG. 25. Once the embolic filter assembly 302 is deployed,oxygenated blood may be infused into the aorta through the tubularcatheter shaft 304. Any potential emboli are captured by the embolicfilter assembly 302 and prevented from entering the neurovasculature orother branches downstream. After use, the embolic filter assembly 302 isreturned to the collapsed position, the catheter 300 is withdrawn fromthe patient, and the purse string suture 318 is tightened to close theaortotomy.

[0073] In general, each of the passive and active deployment methodsdescribed above may be used interchangeably or together in combinationswith each of the embodiments of the perfusion filter catheter and eachof catheter insertion methods which are described above and below.Likewise, many of the features of the embodiments described may be usedin various combinations with one another to create new embodiments,which are considered to be a part of this disclosure, as it would be toocumbersome to describe all of the numerous possible combinations andsubcombinations of the disclosed features.

[0074] Following are a number of alternate embodiments of the perfusionfilter catheter of the present invention illustrating additionalfeatures and variations in the configuration of the invention. Ingeneral, each of the described embodiments may be passively or activelydeployed by the methods described above. Each embodiment of theperfusion filter catheter described can also be adapted for retrogradedeployment via peripheral arterial access, such as femoral or subclavianartery access, or for antegrade or retrograde deployment via directaortic puncture.

[0075]FIGS. 28 and 29 show a perfusion filter catheter 320 having anembolic filter assembly 322 with a graded porosity filter screen 324.The filter screen 324 is attached to a filter support structure 326mounted on a catheter shaft 328 for antegrade or retrograde deployment.The filter screen 324 may be made in each of the configurationsdisclosed herein or any other convenient shape. By way of example, thefilter screen 324 in this embodiment is depicted as being in the shapeof a frustum of a cone. The filter screen 324 has an upstream end 330and a downstream end 332. The upstream end 330 of the filter screen 324has a finer filter mesh than the downstream end 332. Depending on thecapabilities of the fabrication process used, the pore size of thefilter screen 324 may make a gradual transition from the upstream end330 to the downstream end 332 or there may be two or more discrete zonesof varying pore size. In one preferred embodiment, the filter mesh onthe upstream end 330 has a pore size of approximately 5-50 micrometersfor capturing microemboli and macroemboli and the filter mesh on thedownstream end 332 has a pore size of approximately 50-100 micrometersfor capturing macroemboli only. The pore size of the filter screen 324has been greatly exaggerated in FIG. 28 for clarity of illustration.

[0076] In use, the perfuision filter catheter 320 is introduced into theaorta with the embolic filter assembly 322 in a collapsed state withinan outer tube 334, using one of the methods described above. The embolicfilter assembly 322 is advanced across the aortic arch while in thecollapsed state. When the upstream end 336 of the catheter 320 ispositioned in the ascending aorta between the aortic valve and thebrachiocephalic artery, the outer tube 334 is withdrawn and the embolicfilter assembly 322 is either actively or passively deployed, as shownin FIG. 29. Preferably, the embolic filter assembly 292 is dimensionedso that when it is deployed, the upstream end 330 of the filter screen324 is positioned in the vicinity of the ostia for the brachiocephalicartery and the left common carotid artery and the downstream end 332 ofthe filter screen 324 is positioned downstream of this position,preferably in the descending aorta. This configuration assures that allof the perfusate which is destined for the neurovasculature must passthrough the finer, upstream end 330 of the filter screen 324 to removeall microemboli and macroemboli. Whereas, the perfusate which isdestined for the viscera and the lower limbs, which are more tolerant ofsmall emboli, need only pass through the downstream end 332 of thefilter screen 324, so as to remove at least the macroemboli.

[0077]FIG. 30 shows a perfusion filter catheter 340 having alongitudinally fluted embolic filter assembly 342. The embolic filterassembly 342 has a filter screen 344 that is attached at its open distalend 352 to a filter support structure 346 mounted on a catheter shaft348 for antegrade or retrograde deployment. The filter screen 344 has aplurality of longitudinally oriented folds or flutes 350. FIG. 30A is acutaway section of the embolic filter assembly 342 cut along line 30A inFIG. 30 in order to better show the longitudinal flutes 350. Thelongitudinal flutes 350 provide additional surface area to the filterscreen 344 to reduce pressure drop from blood flow across the embolicfilter assembly 342. The longitudinal flutes 350 also serve to hold amajority of the filter screen 344 away from the aortic wall and awayfrom the ostia of the arch vessels. The longitudinally fluted embolicfilter assembly 342 can be adapted for passive or active deployment byany of the methods described above.

[0078]FIG. 31 shows a perfusion filter catheter 360 having alongitudinally ribbed embolic filter assembly 362. The embolic filterassembly 362 has a filter screen 364 that is attached at its open distalend 372 to a filter support structure 366 mounted on a catheter shaft368 for antegrade or retrograde deployment. The filter screen 364 may beconfigured as a conical, trumpet, longitudinally fluted or other styleof filter screen. The embolic filter assembly 362 has a plurality oflongitudinally oriented ribs 370 positioned around the exterior of thefilter screen 364. FIG. 31A is a cutaway section of the embolic filterassembly 362 cut along line 31A in FIG. 31 in order to better show thelongitudinally oriented ribs 370. The longitudinal ribs 370 serve asstandoff members to center the filter screen 364 within the aorta so ashold a majority of the filter screen 364 away from the aortic wall andaway from the ostia of the arch vessels. The longitudinally ribbedembolic filter assembly 362 can be adapted for passive or activedeployment by any of the methods described above.

[0079]FIG. 32 shows a perfusion filter catheter 380 having an embolicfilter assembly 382 that is surrounded by a cage 394 of standoff members396. The embolic filter assembly 382 has a filter screen 384 that isattached at its open distal end 392 to a filter support structure 386mounted on a catheter shaft 388 for antegrade or retrograde deployment.The filter screen 384 may be configured as a conical, trumpet,longitudinally fluted or other style of filter screen. The embolicfilter assembly 382 further includes a plurality of standoff members 396that form a cage 394 surrounding the filter screen 384. The standoffmembers 396 may be made of a resilient polymer or metal, such as anelastic or superelastic alloy, or a shape-memory material. The geometryof the standoff members 396 is quite variable. By way of example, FIG.32 depicts the standoff members 396 as a plurality of longitudinallyoriented wires which, together, form a roughly cylindrical cage 394.Other possible configurations include circumferential members, diagonalmembers, and combinations thereof. The standoff members 396 of the cage394 serve to center the filter screen 384 within the aorta so as hold amajority of the filter screen 384 away from the aortic wall and awayfrom the ostia of the arch vessels. The embolic filter assembly 382 andthe standoff members 396 of the cage 394 can be adapted for passive oractive deployment by any of the methods described above.

[0080]FIG. 33 shows a perfusion filter catheter 400 having an embolicfilter assembly 402 that is 10 surrounded by a cage 414 of coiled wirestandoff members 416. The embolic filter assembly 402 has a filterscreen 404 that is attached at its open distal end 412 to a filtersupport structure 406 mounted on a catheter shaft 408 for antegrade orretrograde deployment. The filter screen 404 may be configured as aconical, trumpet, longitudinally fluted or other style of filter screen.The embolic filter assembly 402 further includes a plurality of looselycoiled wire standoff members 416 which form a cage 414 surrounding thefilter screen 404. The coiled standoff members 416 may be made of aresilient polymer or metal, such as an elastic or superelastic alloy, ora shape-memory material. The coiled standoff members 416 of the cage 414serve to center the filter screen 404 within the aorta so as hold amajority of the filter screen 404 away from the aortic wall and awayfrom the ostia of the arch vessels. The embolic filter assembly 402 andthe standoff members 416 of the cage 414 can be adapted for passive oractive deployment by any of the methods described above.

[0081]FIG. 34 shows a perfusion filter catheter 420 having an embolicfilter assembly 422 that is surrounded by a cage 434 of coarse netting436. The embolic filter assembly 422 has a filter screen 424 that isattached at its open distal end 432 to a filter support structure 426mounted on a catheter shaft 428 for antegrade or retrograde deployment.The filter screen 424 may be configured as a conical, trumpet,longitudinally fluted or other style of filter screen. The embolicfilter assembly 422 further includes a coarse netting 436, which forms aroughly cylindrical cage 434 surrounding the filter screen 424. Thenetting 436 may be made of a resilient polymer or metal, such as anelastic or superelastic alloy, or a shape-memory material. The netting436 of the cage 434 serves to center the filter screen 424 within theaorta so as hold a majority of the filter screen 424 away from theaortic wall and away from the ostia of the arch vessels. The embolicfilter assembly 422 and the coarse netting 436 of the cage 434 can beadapted for passive or active deployment by any of the methods describedabove.

[0082]FIG. 35 shows a cutaway view of a perfusion filter catheter 440having an embolic filter assembly 442 that is surrounded by a fender 454made from a porous foam or a fibrous network 456. The embolic filterassembly 442 has a filter screen 444 that is attached at its open distalend 452 to a filter support structure 446 mounted on a catheter shaft448 for antegrade or retrograde deployment. The filter screen 444 may beconfigured as a conical, trumpet, longitudinally fluted or other styleof filter screen. The embolic filter assembly 442 further includes aroughly cylindrical fender 454 made from a highly porous foam or afibrous network 456, which surrounds the filter screen 444. The fender454 may be made of a highly porous open cell polymer foam or a networkof polymeric fibers. The fender 454 serves to center the filter screen444 within the aorta so as hold a majority of the filter screen 444 awayfrom the aortic wall and away from the ostia of the arch vessels. Theembolic filter assembly 442 and the fender 454 can be adapted forpassive or active deployment or a combination thereof.

[0083]FIGS. 36 and 37 show an alternate embodiment of a perfusion filtercatheter 460 with a passively deployed embolic filter assembly 462. Theembolic filter assembly 462 has a filter screen 464 that is attached atits open distal end 474 to a filter support structure 466 mounted on acatheter shaft 468 for antegrade or retrograde deployment. The proximalend 476 of the filter screen 464 is sealingly attached to the cathetershaft 468. The filter screen 464 may be configured as a conical, trumpetor other style of filter screen. The filter support structure 466 has anouter hoop 470 which is attached by a perpendicular leg 472 to thecatheter shaft 468. Preferably, the outer hoop 470 is made of aresilient polymer or metal, such as an elastic or superelastic alloy, orpossibly a shape-memory material. The filter support structure 466, inthis embodiment, has no struts. Optionally, the distal end 478 of thecatheter shaft 468 may be curved toward the center of the outer hoop 470to help center the perfusion port 480 located at the distal end of thecatheter shaft 468 within the aorta when the catheter 460 is deployed.Also, the perfusion port 480 may optionally include additional sideports or a flow diffuser, as shown, to reduce jetting when oxygenatedblood is infused through the perfusion lumen 482.

[0084] The perfusion filter catheter 460 is prepared for use by bendingthe outer hoop 470 in the proximal direction or wrapping it around thecatheter shaft 468, then folding or wrapping the material of the filterscreen 464 around the catheter shaft 468. An outer tube 484 is placedover the embolic filter assembly 462 to hold it in the collapsedposition, as shown in FIG. 37. The catheter 460 is introduced and theembolic filter assembly 462 is advanced across the aortic arch while inthe collapsed state. When the distal end 474 of the embolic filterassembly 462 is positioned in the ascending aorta between the aorticvalve and the brachiocephalic artery, the outer tube 484 is withdrawnand the resilient outer hoop 470 expands to deploy the embolic filterassembly 462, as shown in FIG. 36. The outer hoop 470 and the distal end474 of the filter screen 464 will seal against the aortic wall. Afteruse, the embolic filter assembly 462 is returned to the collapsedposition by advancing the outer tube 484 distally over the filter screen464 and the filter support structure 466, then the catheter 460 iswithdrawn from the patient.

[0085] FIGS. 38-41 show an alternate embodiment of a perfusion filtercatheter 490 with an actively deployed embolic filter assembly 492. Theembolic filter assembly 492 has a filter screen 494 with a sewn tubularchannel 496 which extends circumferentially around the open distal end498 of the filter screen 494. The distal end 498 of the filter screen494 is attached on one side to the catheter shaft 504, and the proximalend 506 of the filter screen 494 is sealingly attached to the cathetershaft 504. The filter screen 494 may be configured as a conical, trumpetor other style of filter screen. The filter support structure in thisembodiment consists of a preshaped, superelastic actuation wire 500,which, when the embolic filter assembly 492 is in the collapsed state,resides in a second lumen 502 within the catheter shaft 504. Preferably,the actuation wire 500 has a bead or small loop 508 at its distal end tocreate a blunt, non-piercing tip. The second lumen 502 of the cathetershaft 504 communicates with the tubular channel 496 at the distal end498 of the filter screen 494. When the actuation wire 500 is extended,it forms a hoop as it passes through the tubular channel 496 of thefilter screen 494.

[0086] Optionally, the distal end 510 of the catheter shaft 504 may becurved toward the center of the embolic filter assembly 492 to helpcenter the perfusion port 510 located at the distal end of the cathetershaft 504 within the aorta when the catheter 490 is deployed. Also, theperfusion port 510 may optionally include additional side ports or aflow diffuser, as shown, to reduce jetting when oxygenated blood isinfused through the perfusion lumen 512 during cardiopulmonary bypass.

[0087] The perfusion filter catheter 490 is prepared for use bywithdrawing the actuation wire 500 into the second lumen 502, thenfolding or wrapping the flexible material of the filter screen 494around the catheter shaft 504. Optionally, an outer tube 514 may beplaced over the embolic filter assembly 492 to hold it in the collapsedposition, as shown in FIG. 38. The catheter 490 is introduced and theembolic filter assembly 492 is advanced across the aortic arch while inthe collapsed state. When the distal end 498 of the embolic filterassembly 492 is positioned in the ascending aorta between the aorticvalve and the brachiocephalic artery, the outer tube 514 is withdrawn,which allows the filter screen 494 to unwrap from the catheter shaft504, as shown in FIG. 39.

[0088] Then, the preshaped, superelastic actuation wire 500 is advanceddistally so that it begins to form a hoop as it passes through thetubular channel 496 at the distal end 498 of the filter screen 494, asshown in FIG. 40. The actuation wire 500 is further advanced until itforms a complete hoop, as shown in FIG. 41, thereby sealing the distalend 498 of the filter screen 494 against the aortic wall. After use, theembolic filter assembly 492 is returned to the collapsed position asdescribed above, then the catheter 490 is withdrawn from the patient.

[0089]FIGS. 42 and 43 show another alternate embodiment of a perfusionfilter catheter 520 with an actively deployed embolic filter assembly522. The embolic filter assembly 522 has a filter screen 524 with a sewntubular channel 526 which extends circumferentially around the opendistal end 528 of the filter screen 524. The distal end 528 of thefilter screen 524 is attached on one side to the catheter shaft 534, andthe proximal end 536 of the filter screen 524 is sealingly attached tothe catheter shaft 534. The filter screen 524 may be configured as aconical, trumpet or other style of filter screen. The filter supportstructure in this embodiment consists of a preshaped, elastic orsuperelastic wire loop 530. The wire loop 530 passes through the tubularchannel 526 at the distal end 528 of the filter screen 524. When theembolic filter assembly 522 is in the collapsed position, the wire loop530 is withdrawn into a second lumen 532 within the catheter shaft 534,as shown in FIG. 42. In the collapsed position, the wire loop 530 actsas a purse string to close the filter screen 524 tightly around thecatheter shaft 534. When the wire loop 530 is advanced distally, itforms a hoop that holds the distal end 528 of the filter screen 524open, as shown in FIG. 43.

[0090] Optionally, the distal end 540 of the catheter shaft 534 may becurved toward the center of the embolic filter assembly 522 to helpcenter the perfusion port 542 located at the distal end of the cathetershaft 534 within the aorta when the catheter 520 is deployed. Also, theperfusion port 540 may optionally include additional side ports or aflow diffuser, as shown, to reduce jetting when oxygenated blood isinfused through the perfusion lumen 544 during cardiopulmonary bypass.

[0091] The perfusion filter catheter 520 is prepared for use bywithdrawing the wire loop 530 into the second lumen 532, then folding orwrapping the flexible material of the filter screen 524 around thecatheter shaft 534. Optionally, an outer tube 538 may be placed over theembolic filter assembly 522 to hold it in the collapsed position. Thecatheter 520 is introduced and the embolic filter assembly 522 isadvanced across the aortic arch while in the collapsed state. When thedistal end 528 of the embolic filter assembly 522 is positioned in theascending aorta between the aortic valve and the brachiocephalic artery,the outer tube 538 is withdrawn, and the preshaped, superelastic wireloop 530 is advanced distally so that it forms a hoop that holds thedistal end 528 of the filter screen 524 open and seals against theaortic wall. The inherent adjustability of the wire loop 530 used todeploy the embolic filter assembly 522 naturally compensates forpatient-to-patient variations in aortic luminal diameter. After use, theembolic filter assembly 522 is returned to the collapsed position bywithdrawing the wire loop 530 into the second lumen 532. This closes thefilter screen 524 like a purse string to capture any potential embolithat are in the embolic filter assembly 522. Then, the catheter 520 iswithdrawn from the patient.

[0092]FIGS. 44 and 45 show another alternate embodiment of a perfusionfilter catheter 550 with an actively deployed embolic filter assembly552. The embolic filter assembly 552 has a filter screen 554 with anopen distal end 558 that is attached to a toroidal balloon 560. Thetoroidal balloon 560 is attached on one side to the catheter shaft 564and it is fluidly connected to an inflation lumen 562 within thecatheter shaft 564. The proximal end 566 of the filter screen 554 issealingly attached to the catheter shaft 564. The filter screen 554 maybe configured as a conical, trumpet or other style of filter screen.Optionally, the distal end 570 of the catheter shaft 564 may be curvedtoward the center of the embolic filter assembly 552 to help center theperfusion port 572 located at the distal end of the catheter shaft 564within the aorta when the catheter 550 is deployed. Also, the perfusionport 570 may optionally include additional side ports or a flowdiffuser, as shown, to reduce jetting when oxygenated blood is infusedthrough the perfusion lumen 574 during cardiopulmonary bypass.

[0093] The perfusion filter catheter 550 is prepared for use bydeflating the toroidal balloon 560, then folding or wrapping thedeflated toroidal balloon 560 and the filter screen 554 around thecatheter shaft 564. Optionally, an outer tube 564 may be placed over theembolic filter assembly 552 to hold it in the collapsed position, asshown in FIG. 44. The catheter 550 is introduced and the embolic filterassembly 552 is advanced across the aortic arch while in the collapsedstate. When the distal end 558 of the embolic filter assembly 552 ispositioned in the ascending aorta between the aortic valve and thebrachiocephalic artery, the outer tube 564 is pulled back to expose theembolic filter assembly 552. Then, the embolic filter assembly 202 isdeployed by inflating the toroidal balloon 560 with fluid injectedthrough the inflation lumen 562, as shown in FIG. 45. When the embolicfilter assembly 552 is deployed, the toroidal balloon 560 seals againstthe inner wall of the aorta. Preferably, at least the outer wall of thetoroidal balloon 560 is somewhat compliant when inflated in order tocompensate for patient-to-patient variations in aortic luminal diameter.After use, the toroidal balloon 560 is deflated and the catheter 550 iswithdrawn from the patient.

[0094] Ideally, it is preferable that the embolic filter assembly of theperfusion filter catheter be deployed continuously throughout the entireperiod of cardiopulmonary bypass or extracorporeal perfusion. It is mostcritical, however, that the embolic filter assembly be deployed duringperiods when the potential for embolization is the highest, such asduring manipulations of the heart and the aorta, during clamping andunclamping of the aorta and during the initial period after the heart isrestarted following cardioplegic arrest. It has been previously statedthat, for continuous deployment of a filter device in the aortic lumen,it is desirable for the filter mesh to have a surface area of 3-10 in².The shallow, cone-shaped aortic filter devices illustrated in the knownprior art only manage to provide surface areas at the lower end of thisdesired range in the largest of human aortas (approximately 3.0-3.9 in²in aortas of 3.5-4.0 cm diameter estimated based on the drawings anddescriptions in the prior art disclosures) and in no cases are thereembodiments disclosed which could provide surface areas in the middleand upper end of this range or that could even meet the minimum limit ofthis desired range in more typically sized aortas in the range of2.5-3.5 cm diameter. Consequently, it is the opinion of the presentinventors that the prior art does not provide an adequate solution tothe technical problem that it illuminates.

[0095] The solution to this dilemma is to provide a filter assembly thathas a greater ratio of filter surface area to the cross-sectional areaof the aortic lumen. (The cross-sectional area of the aortic lumen beingapproximately equal to the area of the open upstream end of the embolicfilter assembly at its deployed diameter within the aorta.) Preferably,the embolic filter assembly should provide a ratio of the filter surfacearea to the cross-sectional area of the aortic lumen of greater thanapproximately 2, more preferably greater than 3, more preferably greaterthan 4, more preferably greater than 5 and most preferably greater than6. With these ratios of the filter surface area to the cross-sectionalarea of the aortic lumen, it is possible to achieve a filter meshsurface area of 3-10 in² or greater in all typical adult human aortasranging from 2.0 to 4.0 cm in diameter. Furthermore, given the embolicfilter assembly structures that have been disclosed herein, it isenvisioned that ratios of the filter surface area to the cross-sectionalarea of the aortic lumen of 8, 10, 12 and even greater are readilyachievable. Higher ratios such as these are desirable as they allow avery fine filter mesh to be utilized to effectively capture bothmacroemboli and microemboli without compromising the aortic blood flow.Along with this, it is preferable to utilize an embolic filter assemblystructure or other means that maximizes the effective surface area ofthe filter mesh by holding at least a majority of the filter mesh awayfrom the aortic wall or any other structures that might potentiallyobstruct flow through the filter mesh.

[0096] To further illustrate this point, the following are given asexamples of embolic filter assemblies exhibiting the desired range ofratios of the filter surface area to the cross-sectional area of theaortic lumen. These examples are merely illustrative of some of thepossible embodiments of the embolic filter assembly and should not beinterpreted as limiting in any way to the scope of the presentinvention. Turning first to FIGS. 1-3, there is illustrated an embolicfilter assembly that is approximately conical in shape. In order toachieve a ratio of the filter surface area to the cross-sectional areaof the aortic lumen of greater than approximately 2, a conical filterassembly must have a filter length L of greater than the aortic diameterD. To achieve a ratio of the filter surface area to the cross-sectionalarea of the aortic lumen of greater than approximately 4, a conicalfilter assembly must have a filter length L of greater than twice theaortic diameter D. To achieve a ratio of the filter surface area to thecross-sectional area of the aortic lumen of greater than approximately6, a conical filter assembly must have a filter length L of greater thanthree times the aortic diameter D. With these ratios of the filtersurface area to the cross-sectional area of the aortic lumen, it ispossible to achieve a filter mesh surface area of 3-10 in² or greater inall typical adult human aortas ranging from 2.0 to 4.0 cm in diameter.Greater length to diameter ratios will provide more improved ratios ofthe filter surface area to the cross-sectional area of the aortic lumen.

[0097] Turning next to FIGS. 7-8, 15-17 and 25-27, there are illustratedembolic filter assemblies having an approximately trumpet-shapedgeometry that includes an approximately conical upstream sectionconnected to an approximately cylindrical extension with a closeddownstream end. This geometry provides an improvement in the ratio ofthe filter surface area to the cross-sectional area of the aortic lumenof approximately 15 to 50 percent compared with the simple conicalgeometry. Thus, even greater ratios of the filter surface area to thecross-sectional area of the aortic lumen are readily achieved using thistrumpet-shaped geometry. Further improvements of the ratio of the filtersurface area to the cross-sectional area of the aortic lumen can berealized with the convoluted embolic filter assemblies illustrated inFIGS. 18-20, 20-23 and 30. With these convoluted geometries, ratios ofthe filter surface area to the cross-sectional area of the aortic lumenof 2-12 or even greater can be achieved.

[0098] Each of the embodiments of the invention described herein may beused for administration of standard cardiopulmonary bypass andcardioplegic arrest by combining the aortic filter catheter with astandard aortic crossclamp and a standard arterial perfusion cannulainserted into the ascending aorta between the crossclamp and the embolicfilter assembly. Where the aortic filter catheter includes an integralperfusion lumen, the CPB system can be simplified by the eliminating theseparate arterial perfusion cannula. The CPB system can be furthersimplified by incorporating an aortic occlusion device into the aorticfilter catheter and eliminating the aortic crossclamp. Such a systemwould allow percutaneous transluminal administration of cardiopulmonarybypass and cardioplegic arrest with protection from undesirable embolicevents.

[0099] FIGS. 46-50 show the operation of an embodiment of a perfusionfilter catheter 600 that combines an embolic filter assembly 602 with atoroidal balloon aortic occlusion device 604. The embolic filterassembly 602 and the toroidal balloon aortic occlusion device 604 aremounted on an elongated catheter shaft 606 that may be adapted forperipheral introduction via the femoral artery or subclavian artery orfor central insertion directly into the ascending aorta. The toroidalballoon aortic occlusion device 604 is connected to an inflation lumenwithin the elongated catheter shaft 606. A cardioplegia lumen, which mayalso serve as a guidewire lumen, connects to a cardioplegia port 608 atthe distal end of the catheter shaft 606. A perfusion lumen connects toone or more perfusion ports 610 located on the catheter shaft 606downstream from the toroidal balloon aortic occlusion device 604, butupstream of the embolic filter assembly 602.

[0100]FIG. 46 shows the perfusion filter catheter 600 in the collapsedor undeployed state with the embolic filter assembly 602 and thetoroidal balloon aortic occlusion device 604 collapsed or folded aboutthe elongated catheter shaft 606. The perfuision filter catheter 600 isinserted in the collapsed state and advanced into the patient'sascending aorta until the embolic filter assembly 602 is positionedbetween the coronary ostia and the brachiocephalic artery. The toroidalballoon aortic occlusion device 604 is then inflated to expand anddeploy the embolic filter assembly 602, as shown in FIG. 47. The embolicfilter assembly 602 may assume a simple conical shape or, morepreferably, one of the surface area increasing geometries describedabove. In addition, the embolic filter assembly 602 may include astructure or other means to hold the filter material apart from theaortic wall to maximize the effective filter area. With the embolicfilter assembly 602 deployed, cardiopulmonary bypass with embolicprotection can be started through the perfusion ports 610.

[0101] When it is desired to initiate cardioplegic arrest, the toroidalballoon aortic occlusion device 604 is further inflated until it expandsinward to occlude the aortic lumen, as shown in FIG. 48. A cardioplegicagent is infused through the cardioplegia port 608 and into the coronaryarteries to arrest the heart. Oxygenated blood continues to be infusedthrough the perfusion ports 610. After completion of the surgicalprocedure, the toroidal balloon aortic occlusion device 604 is partiallydeflated, leaving the embolic filter assembly 602 deployed, as shown inFIG. 49. Oxygenated blood enters the coronary arteries to restart theheart beating. If any embolic materials 612 are dislodged duringmanipulation of the heart or when the heart resumes beating, they willbe captured by the embolic filter assembly 602. Once the patient isweaned off of bypass, the toroidal balloon aortic occlusion device 604is deflated to collapse the embolic filter assembly 602, as shown inFIG. 50. Any potential emboli are trapped within the embolic filterassembly 602 and can be removed along with the catheter 600.

[0102]FIG. 51 shows an embodiment of a perfusion filter catheter 620that combines an embolic filter assembly 622 with an inflatable balloonaortic occlusion device 624. The embolic filter assembly 622 may be anyone of the actively or passively deployed embolic filter assembliesdescribed herein. Preferably, the inflatable balloon aortic occlusiondevice 624 is an 5 elastomeric balloon of sufficient inflated diameterto occlude the ascending aorta and is mounted on the elongated cathetershaft 626 upstream of the embolic filter assembly 622. Alternatively,the inflatable balloon aortic occlusion device 624 may be positioned toocclude the inlet end of the embolic filter assembly 622 to minimize thearea of contact between the perfusion filter catheter 620 and the aorticwall. The inflatable balloon aortic occlusion device 624 is connected toan inflation lumen within the elongated catheter shaft 626. Acardioplegia lumen, which may also serve as a guidewire lumen, connectsto a cardioplegia port 628 at the distal end of the catheter shaft 626.A perfusion lumen connects to one or more perfusion ports 630 located onthe catheter shaft 626 downstream from the inflatable balloon aorticocclusion device 624, but upstream of the embolic filter assembly 622.The operation of the perfusion filter catheter 620 of FIG. 51 is quitesimilar to that described for the embodiment of FIGS. 46-50.

[0103]FIG. 52 shows an embodiment of a perfusion filter catheter 640that combines an embolic filter assembly 642 with a selectivelydeployable external catheter flow control valve 644. The embolic filterassembly 642 may be any one of the actively or passively deployedembolic filter assemblies described herein. The selectively deployableexternal catheter flow control valve 644 is mounted on the elongatedcatheter shaft 646 upstream of the embolic filter assembly 642.Alternatively, the selectively deployable external catheter flow controlvalve 644 may be positioned to occlude the inlet end of the embolicfilter assembly 642 to minimize the area of contact between theperfusion filter catheter 640 and the aortic wall. Selectivelydeployable external catheter flow control valves suitable for thisapplication are described in commonly owned, copending U.S. patentapplications Ser. Nos. 08/665,635, 08/664,361 and 08/664,360, filed Jun.17, 1996, which are hereby incorporated by reference in their entirety.The elongated catheter shaft 646 may include one or more deploymentlumens as needed for actuating the external catheter flow control valve644. A cardioplegia lumen, which may also serve as a guidewire lumen,connects to a cardioplegia port 648 at the distal end of the cathetershaft 646. A perfusion lumen connects to one or more perfusion ports 650located on the catheter shaft 646 downstream from the external catheterflow control valve 644, but upstream of the embolic filter assembly 622.The operation of the perfusion filter catheter 640 of FIG. 52 is quitesimilar to that described for the embodiment of FIGS. 46-50.

[0104]FIG. 53 shows an additional feature of the present invention thatmay be used in combination with many of the features and embodimentspreviously described. FIG. 53 shows an embodiment of a perfusion filtercatheter 660 with an embolic filter assembly 662 having areas ofdifferent filter porosity. The embolic filter assembly 662 is mounted onan elongated catheter shaft 666 that may be adapted for peripheralintroduction via the femoral artery or subclavian artery or for centralinsertion directly into the ascending aorta. The embolic filter assembly662 may resemble any one of the actively or passively deployed embolicfilter assemblies described herein. Preferably, the embolic filterassembly 662 assumes one of the surface area increasing geometriesdescribed above, such as a trumpet-style embolic filter assembly 662 asshown. The embolic filter assembly 662 is divided along a longitudinaldividing line into areas of different filter porosity. In a preferredembodiment, the embolic filter assembly 662 has an upper portion 664 offiner porosity facing toward the aortic arch vessels and a lower portion668 of courser porosity facing away from the aortic arch vessels.Preferably, the elongated catheter shaft 666 will have a preformed curveto help orient the upper portion 664 and the lower portion 668 of theembolic filter assembly 662 in the proper position once deployed. Thefilter mesh of the upper portion 664 may be selected to exclude bothmacroemboli and microemboli, and the filter mesh of the lower portion668 may be selected to exclude macroemboli only. Alternatively, theupper portion 664 may be impermeable so as to act like a shunt to directpotential emboli downstream away from the aortic arch vessels.

[0105] Another feature that may be combined with the features andembodiments of the present invention is an aortic transilluminationsystem for locating and monitoring the position of the catheter, thefilter and the optional occlusion devices without fluoroscopy bytransillumination of the aortic wall. Aortic transillumination systemsusing optical fibers and/or light emitting diodes or lasers suitable forthis application are described in commonly owned, copending U.S. patentapplication Ser. No. 60/088,652, filed Jun. 9, 1998, which is herebyincorporated by reference in its entirety. By way of example, FIG. 54shows an embodiment of a perfusion filter catheter 670 with a fiberopticsystem for aortic transillumination. A first optical fiber 684 ispositioned near a distal end of the perfusion filter catheter 670,upstream of the embolic filter assembly 672, so that it will emit afirst laterally directed beam of light. A second optical fiber 672 ispositioned on the outer rim of the filter support structure 674 so thatit will emit a second laterally directed beam of light. An opticalcoupling 682 at the proximal end of the perfusion filter catheter 670connects the optical fibers 684, 672 to a light source 680 by way of anoptical cable 678. The light beams emitted by the optical fibers 684,672 are visible through the aortic wall and can be used to locate andmonitor the position and the deployment state of the perfusion filtercatheter 670 and the embolic filter assembly 672. Similarly, inembodiments of the perfusion filter catheter utilizing an aorticocclusion device, one or more optical fibers or other light emittingdevices may be positioned on the aortic occlusion device to locate andmonitor its position and state of deployment.

[0106] Likewise, the features and embodiments of the present inventionmay also be combined with a bumper location device for facilitatingcatheter insertion and positioning by providing tactile feedback whenthe catheter device contacts the aortic valve. Bumper location devicessuitable for this application are described in commonly owned, copendingU.S. patent application Ser. Nos. 60/060,158, filed Sep. 26, 1997, andNo. 60/073,681, filed Feb. 4, 1998, which are hereby incorporated byreference in their entirety.

[0107] While the present invention has been described herein withrespect to the exemplary embodiments and the best mode for practicingthe invention, it will be apparent to one of ordinary skill in the artthat many modifications, improvements and subcombinations of the variousembodiments, adaptations and variations can be made to the inventionwithout departing from the spirit and scope thereof.

What is claimed is:
 1. An aortic filter catheter comprising: anelongated catheter shaft, an embolic filter assembly mounted on saidcatheter shaft, said embolic filter assembly including a porous filtermesh, said embolic filter assembly being expandable to engage an innersurface of a patient's aorta, and an aortic occlusion device mounted onsaid elongated catheter shaft.
 2. The aortic filter catheter of claim 1,wherein said aortic occlusion device is mounted on said elongatedcatheter shaft upstream of said embolic filter assembly.
 3. The aorticfilter catheter of claim 1, wherein said aortic occlusion devicecomprises a toroidal balloon occlusion device, said toroidal balloonocclusion device having an uninflated state, a first inflated state inwhich said toroidal balloon occlusion device engages the inner surfaceof the aorta and in which said toroidal balloon occlusion device has anopen central passage permitting fluid flow therethrough, and a secondinflated state in which said central passage of said toroidal balloonocclusion device closes preventing fluid flow therethrough.
 4. Theaortic filter catheter of claim 1, wherein said aortic occlusion devicecomprises an inflatable balloon expandable to occlude the aortic lumen.5. The aortic filter catheter of claim 4, wherein said inflatableballoon is mounted on said elongated catheter shaft upstream of saidembolic filter assembly.
 6. The aortic filter catheter of claim 1,wherein said aortic occlusion device comprises an external catheter flowcontrol valve expandable to occlude the aortic lumen.
 7. The aorticfilter catheter of claim 6, wherein said external catheter flow controlvalve is mounted on said elongated catheter shaft upstream of saidembolic filter assembly.
 8. The aortic filter catheter of claim 1,wherein said embolic filter assembly is configured to expand passivelyin response to blood flow in the aorta.
 9. The aortic filter catheter ofclaim 1, wherein said embolic filter assembly is resiliently biasedtoward the expanded state.
 10. The aortic filter catheter of claim 1,further comprising a perfusion lumen within said elongated cathetershaft, said perfusion lumen being fluidly connected to a perfusion portlocated on said elongated catheter shaft upstream of said filter meshand downstream of said aortic occlusion device.
 11. The aortic filtercatheter of claim 10, further comprising a distal lumen within saidelongated catheter shaft, said distal lumen being fluidly connected to adistal port on said elongated catheter shaft upstream of said aorticocclusion device.
 12. The aortic filter catheter of claim 1, whereinsaid embolic filter assembly is configured with a conical upstreamsection and an approximately cylindrical extension extending downstreamof said conical upstream section.
 13. The aortic filter catheter ofclaim 1, wherein said embolic filter assembly includes a means toactively expand said embolic filter assembly within the aorta.
 14. Theaortic filter catheter of claim 13, wherein said means to activelyexpand said embolic filter assembly comprises a plurality of actuationmembers connected to an outer periphery of said embolic filter assembly.15. The aortic filter catheter of claim 14, wherein said actuationmembers comprise a plurality of actuation wires slidably received withinat least one actuation wire lumen within said elongated catheter shaft,said actuation wires having distal ends connected to the outer peripheryof said embolic filter assembly.
 16. The aortic filter catheter of claim13, wherein said means to actively expand said embolic filter assemblycomprises an extendable and retractable support wire circumscribing anouter periphery of said embolic filter assembly.
 17. The aortic filtercatheter of claim 16, wherein said support wire has a distal endadvanceable and retractable through a channel circumscribing said outerperiphery of said embolic filter assembly.
 18. The aortic filtercatheter of claim 16, wherein said support wire forms an expandable andretractable loop circumscribing said outer periphery of said embolicfilter assembly.
 19. The aortic filter catheter of claim 16, whereinsaid elongated catheter shaft is approximately tangential to said outerperiphery of said embolic filter assembly when said embolic filterassembly is in an expanded state.
 20. The aortic filter catheter ofclaim 1, wherein said embolic filter assembly has an outer periphery andsaid elongated catheter shaft is approximately tangential to said outerperiphery of said embolic filter assembly when said embolic filterassembly is in an expanded state.
 21. The aortic filter catheter ofclaim 20, wherein said elongated catheter shaft has a distal end that iscurved toward a center of an inlet end of said embolic filter assembly.22. The aortic filter catheter of claim 1, further comprising a lightemitting means for directing a beam of light through a wall of theaorta.
 23. The aortic filter catheter of claim 22, wherein said lightemitting means is positioned on an outer periphery of said embolicfilter assembly.
 24. The aortic filter catheter of claim 1, wherein saidembolic filter assembly comprises a first portion of porous filter meshhaving a first porosity and a second portion of porous filter meshhaving a second porosity different from said first porosity.
 25. Theaortic filter catheter of claim 24, wherein said first portion of porousfilter mesh is an upstream portion of the porous filter mesh and saidsecond portion of porous filter mesh is a downstream portion of theporous filter mesh.
 26. The aortic filter catheter of claim 24, whereinsaid first portion of porous filter mesh is separated from said secondportion of porous filter mesh along a longitudinally oriented dividingline.
 27. The aortic filter catheter of claim 1, wherein said filtermesh has a convoluted configuration when said embolic filter assembly isin the expanded state.
 28. The aortic filter catheter of claim 27,wherein said filter mesh has a circumferentially convolutedconfiguration.
 29. The aortic filter catheter of claim 27, wherein saidfilter mesh has a longitudinally convoluted configuration.
 30. Theaortic filter catheter of claim 27, wherein said filter mesh has ahelically convoluted configuration.
 31. An aortic filter cathetercomprising: an elongated catheter shaft, an embolic filter assemblyhaving a porous filter mesh mounted on said catheter shaft, said embolicfilter assembly being expandable to engage an inner surface of apatient's aorta, said embolic filter assembly having an inlet end thatis open to fluid flow when said embolic filter assembly is in anexpanded state, and a toroidal balloon occlusion device mounted at saidinlet end of said embolic filter assembly, said toroidal balloonocclusion device having an uninflated state, a first inflated state inwhich said toroidal balloon occlusion device engages the inner surfaceof the aorta and in which said toroidal balloon occlusion device has anopen central passage permitting fluid flow therethrough, and a secondinflated state in which said central passage of said toroidal balloonocclusion device closes preventing fluid flow therethrough.
 32. Theaortic filter catheter of claim 31, wherein said elongated cathetershaft is approximately tangential to said inlet end of said embolicfilter assembly when said embolic filter assembly is in the expandedstate.
 33. The aortic filter catheter of claim 31, wherein said inletend of said embolic filter assembly is connected to said elongatedcatheter shaft by a plurality of struts.
 34. The aortic filter catheterof claim 31, further comprising a perfusion lumen within said elongatedcatheter shaft, said perfusion lumen being fluidly connected to aperfusion port located on said elongated catheter shaft upstream of saidfilter mesh and downstream of said toroidal balloon occlusion device.35. The aortic filter catheter of claim 34, further comprising a distallumen within said elongated catheter shaft, said distal lumen beingfluidly connected to a distal port on said elongated catheter shaftupstream of said toroidal balloon occlusion device.
 36. A methodcomprising: introducing an elongated tubular shaft of an aortic filtercatheter into a patient's aorta; positioning an embolic filter assemblyhaving a porous filter mesh mounted on said elongated tubular shaftwithin the patient's ascending aorta; expanding said embolic filterassembly to engage an inner surface of the patient's ascending aorta;and occluding the patient's ascending aorta with an aortic occlusiondevice mounted on said elongated tubular shaft.
 37. The method of claim36, wherein said aortic occlusion device is mounted on said elongatedcatheter shaft upstream of said embolic filter assembly.
 38. The methodof claim 36, further comprising perfusing oxygenated blood through aperfusion lumen within said elongated tubular shaft into the patient'saorta.
 39. The method of claim 36, further comprising perfusingoxygenated blood through a perfusion lumen within said elongated tubularshaft into the patient's aorta upstream of said porous filter mesh anddownstream of said aortic occlusion device.
 40. The method of claim 36,further comprising introducing a cardioplegic agent into the patient'scoronary arteries to induce cardioplegic arrest by infusing thecardioplegic agent into the patient's aorta upstream of said aorticocclusion device.
 41. The method of claim 36, further comprisingmonitoring the position and deployment state of said aortic filtercatheter by directing a beam of light from said aortic filter catheterthrough a wall of the patient's aorta and observing the transmittedlight beam external to the aorta.
 42. The method of claim 36, whereinsaid aortic occlusion device comprises an inflatable balloon expandableto occlude the aortic lumen.
 43. The method of claim 36, wherein saidaortic occlusion device comprises an external catheter flow controlvalve expandable to occlude the aortic lumen.